Rofecoxib, a specific inhibitor of cyclooxygenase 2, with clinical efficacy comparable with that of diclofenac sodium: results of a one-year, randomized, clinical trial in patients with osteoarthritis of the knee and hip. Rofecoxib Phase III Protocol 035 Study Group

Arthritis Rheum. 2000 May;43(5):978-87. doi: 10.1002/1529-0131(200005)43:5<978::AID-ANR4>3.0.CO;2-0.


Objective: To compare the clinical efficacy of rofecoxib, a specific inhibitor of cyclooxygenase 2 (COX-2), with that of diclofenac in patients with osteoarthritis (OA) and to evaluate the safety and tolerability of rofecoxib.

Methods: We performed a randomized, double-blind, active comparator-controlled trial in 784 adults with OA of the knee or hip. Patients were randomized to 1 of 3 treatment groups: 12.5 mg of rofecoxib once daily, 25 mg of rofecoxib once daily, and 50 mg of diclofenac 3 times daily. Clinical efficacy and safety were evaluated over a 1-year continuous treatment period.

Results: Rofecoxib at dosages of 12.5 and 25 mg demonstrated efficacy that was clinically comparable to that of diclofenac, as assessed by all 3 primary end points according to predefined comparability criteria. Results from secondary end points were consistent with those of the primary end points. There were small statistical differences favoring diclofenac for 2 of the end points. All treatments were well tolerated.

Conclusion: Rofecoxib was well tolerated and provided efficacy that was clinically comparable, according to predefined statistical criteria, to that of 150 mg of diclofenac per day in this 1-year study. Specific inhibition of COX-2 provided therapeutic efficacy in OA.

Publication types

  • Clinical Trial
  • Clinical Trial, Phase III
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacokinetics
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use*
  • Cyclooxygenase Inhibitors / therapeutic use*
  • Diclofenac / pharmacokinetics*
  • Diclofenac / therapeutic use*
  • Double-Blind Method
  • Enzyme Inhibitors / pharmacokinetics
  • Enzyme Inhibitors / therapeutic use*
  • Female
  • Humans
  • Lactones / pharmacokinetics*
  • Lactones / therapeutic use*
  • Male
  • Middle Aged
  • Osteoarthritis, Hip / drug therapy
  • Osteoarthritis, Knee / drug therapy
  • Sulfones
  • Therapeutic Equivalency


  • Anti-Inflammatory Agents, Non-Steroidal
  • Cyclooxygenase Inhibitors
  • Enzyme Inhibitors
  • Lactones
  • Sulfones
  • rofecoxib
  • Diclofenac